1. Field of the Invention
The present invention relates to a wireless power feeding system and a capsule endoscope system applied with the wireless power feeding system. More specifically, the present invention relates to a wireless power feeding system for supplying electric power in accordance with a wireless method and contributing to the improvement of the power reception efficiency of a receiver, and a capsule endoscope system applied with the wireless power feeding system.
2. Description of the Related Art
In recent years, various proposals have been made on a capsule endoscope system, which is a medical system for performing, for example, inspection of a body cavity or the like, and which is configured to include a so-called capsule endoscope and a wireless power feeding device, for example, as in Japanese Unexamined Patent Application Publication No. 2001-224551, for example. The capsule endoscope is a small-sized endoscope storing, in a capsule-shaped chassis, observation means formed by an image pickup optical system and image pickup means, illumination means, communication means, a power supply, power receiving means, and so forth. The wireless power feeding device is applied with a communication device for performing wireless communication with the capsule endoscope, recording means for recording a received signal, and a wireless power feeding system for extracorporeally supplying electrical power to the capsule endoscope by wireless or the like with the use of an AC (alternating current) magnetic field.
A capsule endoscope system disclosed in the above Japanese Unexamined Patent Application Publication No. 2001-224551 is configured to include a capsule endoscope and a wireless power feeding device, for example. The capsule endoscope includes, for example, illumination means for illuminating the interior of a living body, image pickup means for picking up an image of a region illuminated by the illumination means, a transmitting antenna for wirelessly transmitting an image signal obtained by the image pickup means to the outside of the body, and a power receiving coil for receiving electrical energy transmitted from the outside of the body. The wireless power feeding device includes, for example, a power transmitting coil for supplying the electrical energy to the capsule endoscope in accordance with a wireless power feeding method.
According to the above configuration, the electrical energy transmitted from the power transmitting coil of the wireless power feeding device is received by the power receiving coil of the capsule endoscope. Thereby, the electrical energy is fed to the capsule endoscope being used in a body cavity from the wireless power feeding device disposed outside the body.
In the above case, the capsule endoscope system has a characteristic of being capable of obtaining a good power reception efficiency in the power transmission from the wireless power feeding device to the capsule endoscope when the direction of the winding axis of the power receiving coil disposed inside the capsule endoscope matches the direction of magnetic fluxes generated from the power transmitting coil of the wireless power feeding device.